Phenol biodegradation and microbial community dynamics in extractive membrane bioreactor (EMBR) for phenol-laden saline wastewater

An extractive membrane bioreactor (EMBR) for phenol-laden saline wastewater was set up in this study to investigate the variations of phenol removal, extracellular polymeric substance (EPS) release and microbial community dynamics. The gradual release of phenol and the total separation of salt were achieved by silicon rubber tube membrane. Only phenol (55.6-273.9 mg/L) was extracted into microorganism unit from wastewaters containing 1.0-5.0 g/L phenol and 35.0 g/L NaCl. After 82 d of EMBR operation, maximal 273.9 mg/L of phenol was removed in EMBR. Low concentration of phenol in wastewater (2.5 g/L) played a favorable effect on the microbial community structure, community and dynamics. The enumeration of Proteobacteria (30,499 sequences) significantly increased with more released EPS (82.82 mg/gSS) to absorb and degrade phenol, compared to the virgin data without phenol addition. However, high concentration of phenol showed adverse effects on EPS release, microbial abundance and biodiversity.